Apparatus for connecting a coriolis flowmeter flow tube to a flowmeter case

ABSTRACT

A flowmeter having a case enclosing a single straight tube surrounded by a balance bar. The balance bar ends are coupled by means of a brace bar to the flow tube as well as by case connect links to the inner wall of the case. The flow tube ends are coupled to end flanges by means of a raised element having a center opening for sealably receiving the flow tube terminus. The flow tube projects beyond the case end and is sealably coupled to a cone connect element in the case end. A void is defined by the space between the flow tube outer surface and the inner surface of the cone connect element and the end flanges to minimize the surface area of the flow tube that is affected by the weld between the case end and raised element of the end flanges. The case connect links contain out of plane bends to accommodate a change in the effective diameter of the case and the balance bar with respect to each other due to changing thermal conditions. Another embodiment of the invention includes a flowmeter without the end flanges. The flow tube ends project beyond the case ends while being sealably coupled to the cone connect element in the case ends. The flowmeter may be manufactured, tested, and calibrated and stored without a flange. The flowmeter is stored in this condition until its commercial use is imminent at which time it is fitted with the appropriate end flange required by the end user.

FIELD OF THE INVENTION

[0001] This invention relates to a Coriolis flowmeter and in particularto a single tube Coriolis flowmeter structure for connecting thevibrating elements of the Coriolis flowmeter to the flowmeter case. Theinvention further relates to a Coriolis flowmeter that can bemanufactured, tested, calibrated, and stored prior to the attachment ofprocess connection flanges.

PROBLEM

[0002] It is a problem to provide a single flow tube Coriolis flowmeterthat operates satisfactorily over a wide range of variations in theoperating parameters of the flowmeter. These parameters includeoperating temperature, the density of the material flow as well as thematerial pressure and flow rate. A change in material density, thermallyinduced stress in the flow tube, or pressure stress on the flow tube caneach result in an unbalanced condition which effects the accuracy of theflowmeter. Changes in these parameters degrade the static and dynamicisolation of the vibratory elements of the flowmeter. The problem is tokeep the vibratory elements immune from the effects of changes inoperating parameters. The accelerations that result from the change inoperating parameters impair flowmeter accuracy by adding to orsubtracting from the Coriolis acceleration of the material. The unwantedaccelerations cannot be compensated for because they vary with themounting conditions of the flowmeter. In addition, the mountingconditions often change with time and temperature in unknown ways.

[0003] Even though a variation of the material parameters and mountingconditions is to be expected, it is desired that the flowmeter remainoperational and produce accurate output information. It is also desiredthat the structural integrity of the flowmeter elements be maintained asthese parameters vary. It is a goal to design a Coriolis flowmeter sothat it operates with suitable accuracy and does not destroy itself asthe flowmeter elements are subject to varying operating temperatures.Flowmeter designers also desire that the flowmeter calibration willremain constant and flat over a reasonably wide range of materialdensities.

[0004] In order to achieve these design objectives, a Coriolis flowmetermust have a dynamically balanced vibrating structure that operates in acontrolled and predictable manner over a range of operating parametervariations. The flowmeter elements external to the vibrating systemshould not vibrate or communicate vibration to the vibratory system. ACoriolis flowmeter often comprises a single straight flow tubesurrounded by a balance bar and brace bars coupling the balance bar endsto the flow tube. In operation, vibration nodes (regions of novibration) occur between the flow tube and the balance bar. The nodesdefine the length of the flow tube that is subject to Coriolis force.The vibration nodes of the flow tube and the surrounding balance barshould remain in the brace bars over the range of parameters for whichthe flowmeter is designed. Since the balance bar, brace bar, and flowtube comprise a dynamically balanced system, the vibrating mass timesthe vibration velocity of the balance bar should equal the vibratingmass times the vibration velocity of the flow tube. As long as theseconditions are met, and no other unbalanced forces or torques areapplied to the non-vibratory elements of the flowmeter, the vibrationnodes remain in the brace bars and the other flow meter elements remainfree from vibration. However, prior art attempts have all fallen shortof meeting these conditions.

[0005] A prior art attempt to minimize node movement and thecommunication of vibration from the case to the vibratory system isshown in the U.S. Pat. No. 5,473,949 to Cage. This patent discloses astraight tube Coriolis flowmeter having a flow tube and a surroundingbalance bar coupled by brace bars. The design is unique in that eachbrace bar also comprises a portion of each case end of the flowmeter.This geometry uses the mass of the case to keep the vibration nodes nearthe brace bar. For instance, a high density material in the flow tubecauses the vibration nodes to move very slightly into the active portionof the flow tube with the result that the brace bars and case ends (andcase) move in phase with the balance bar. Momentum is conserved sincethe mass times velocity of the case plus the mass times the velocity ofthe balance bar equals the mass times velocity of the flow tube. A lowdensity material causes the node to move slightly into the balance barwith the result that the case moves in phase with the flow tube andmomentum is once again conserved. The problem with the Cage design isthat momentum is conserved by the case moving with the light member. Thevibration is of small amplitude because the case is massive, but it isstill large enough that different mounting conditions can effect theaccuracy of the meter.

[0006] Another example of a prior art flowmeter that attempts tominimize unwanted accelerations is shown in U.S. Pat. No. 5,365,794 toKrohne. This patent discloses a flow tube surrounded by a concentricbalance bar and distinct brace bars that couple the balance bar ends tothe flow tube. In this design the balance bar ends are not connected tothe case as in the Cage design. Furthermore, the inactive portion of theflow tube, external to the brace bar regions, is not connected to any ofthe support structure except by the tube ends that are connected to theflange faces. This structure operates satisfactorily as long the ratioof the vibration amplitude of the flow tube divided by the vibrationamplitude of the balance bar does not vary from its design point. At thedesign point, the torque applied to the brace bars by the flow tubes isequal and opposite to the torque applied to the brace bars by thebalance bar. The result is that the inactive portions of the flow tubeare indeed inactive and remain on the axis of the meter. The problemarises when the material density changes. A high density material causesthe vibration amplitude ratio to change. To conserve momentum thevibration amplitude of the heavy flow tube decreases while the vibrationamplitude of the balance bar increases. The change in amplitude ratiocauses the torques at the brace bar to become mismatched. The higheramplitude balance bar applies more torque to the junction than the loweramplitude flow tube. The inactive portion of the flow tube makes up thetorque difference and bends as a result. Unfortunately, the translationincreases the amplitude of the heavy flow tube and makes the balanceworse. Ultimately, the flow tube (containing the high density material)ends up vibrating in phase with the case and the vibration nodes movefar from their balanced locations and the meter accuracy suffers.

[0007] EPO patent 0,759,542 by Oval (FIGS. 8A and 8B of EPO patent0,759,542) provides a Coriolis flowmeter having a straight flow tubesurrounded by a concentric balance bar whose ends are coupled by caseconnect links to the inner wall of a case. The flow tube ends arecoupled to end flanges. This structure provides dual connection pointsat each end of the flowmeter between the balance bar/flow tube and thecase structure including the end flanges. The case connect link designuses the mass of the case to help reduce the movement of the end nodes(as in the Cage design). However, large changes in the amplitude ratiocause torque unbalance at the brace bars (like the Krohne design) andbending in the inactive regions of the flow tube. While the vibration isless than with the other prior art, it is still sufficient to degradethe meter performance.

[0008] It can therefore be seen from the above that it is a problem ofprior art to provide a Coriolis flowmeter structure for which a shift ofthe material density does not degrade the static and dynamic isolationof the flowmeter's vibratory system and the corresponding reduction inthe accuracy of the meter.

[0009] It is also a problem in the manufacture, calibration and testingof a Coriolis flowmeter to minimize the number of Coriolis flowmeters ofa given model that must be maintained in inventory. The reason for thisis that there are more than twenty different types of end flanges thatmay be coupled to each size of flowmeter. There are perhaps eightdifferent sizes of flowmeter resulting in 120 different meters that needto be stocked in order to have rapid response to sales orders. At a costof several thousand dollars each, the amount of money tied up ininventory can be significant. It is desired that flowmeters be of such adesign that they can be balanced, tested, and calibrated before theflanges are attached. This would enable the stocking of far fewerfinished meters without flanges. The desired flanges would be welded onwith the receipt of each order. Of the prior art meters, only the Cagedesign would be functional without flanges and it has balance problems.The other two prior art designs require that the tube end be welded tothe flange in order to provide the dynamics of the finished meter.

SOLUTION

[0010] The above problems are solved and an advance in the art isachieved by the present invention. In accordance with the presentinvention, three separate connection points are provided at each end ofthe flowmeter between the vibrating structure and the flowmeter caseincluding the end flanges. A first such connection point is in the endflange where the flow tube end is joined to the end flange. A secondconnection point is provided by case connect links which couple thebalance bar ends to the inner wall of the case.

[0011] The third connecting point in each end of the flowmeter isprovided by a circular element termed a cone connect. This thirdconnection point is provided by bonding (usually brazing) the flow tubeto the cone connect element at the flow tube location where it extendsthrough an opening in the case end and projects axially outward towardsthe flow tube end. This cone connect connection is, like the other twoconnections, of limited length in the direction of the tube axis. Thereis a length of unsupported flow tube between the flange connection andthe cone connect and another length of unsupported flow tube between thecone connect and the case connect links. Since these unsupportedportions of the flow tube are not coupled to any other structure, a voidsurrounds these portions of the flow tube. The outermost void (in theneck of the flange) allows the welding of a flange to the case end atthis location without overheating or stressing the flow tube. Also, theamount of heat required to effect a weld at these two locations is farless than would be required if the entirety of this portion of the flowtube was thermally coupled to the entire structure between the endflange and the case end.

[0012] The provision of three points of coupling at each end of the flowtube to the supporting structure of the flowmeter minimizes thecommunication of vibrations to the vibratory structure of the flowmeterthat are generated by extreme conditions of parameters such as materialdensity. It does this by the use of the case connect links to enablevibration amplitude ratio balancing and it uses the cone connect elementto keep unbalanced torque away from the vibratory structure of theflowmeter. The reduced communication of vibrations to the vibratorystructure of the flowmeter increases the accuracy and reduces the effectthat different mounting conditions have on the flowmeter.

[0013] It is a further feature that the flowmeter of the presentinvention is manufactured, tested, and calibrated prior to the time thatthe end flange is actually attached. At this stage of completion, theinternal elements of the flowmeter are fully operational and are sealedor isolated by the cone connect element. The end portions of the flowtube extend axially outward from each of the case ends and their coneconnect elements. Because the case is sealed and the flow tubes arerigidly affixed to the case ends, the tube ends may be temporarilycoupled to a source of material flow at this time. The flowmeter maythen be balanced and calibrated. The flowmeter may be indefinitelystored in this state until an order is received from a customer. Then,the needs of the customer and the details of the end flanges required bythe customer are made known and the appropriate end flanges may becoupled to the flow tube projections and the case ends by suitablewelding operations.

[0014] The calibration and testing and subsequent temporary storage ofthe flowmeter prior to it being connected to end flanges is advantageousin that it minimizes the inventory that otherwise would have to bemaintained by a supplier. If finished flowmeters were required to bestored with over twenty known types of flanges, the inventory would haveto be enormous.

[0015] An alternative embodiment of the invention provides a caseconnect link that is not directly connected at its ends between thebalance bar and the inner wall of the case. Instead, the case connectlink has a bend in its central portion and has its outer end connectedto a flat surface of the cone connect element. In this secondembodiment, the cone connect link is circular as in the first embodimentbut has a larger diameter with the outer circumference of this circularcone connect element engaging the inner circular surface of theflowmeter case end. By this means, the case connect link has sufficientrigidity to prevent relative motion between the balance bar ends and theinner wall of the case. At that the same time, due to the bend in thecase connect link, the case connect link is able to flex and accommodatechanges in the diameter of the balance bar due to thermal changes. Thecircular cone connect element functions as before described in that ithas an opening in its center portion through which the flow tubeextends. It differs in that the large outer diameter of the cone connectallows relative axial movement between its outer and inner connectionpoints. This compliance can lower the thermal stress in the flow tube.The cone connect element of this embodiment, like the previousembodiment, also has sufficient rigidity in the radial direction toterminate the dynamic portion of the flow tube and allow balancing andcalibration prior to flange welding. It also seals the case interiorfrom the environment

[0016] It can therefore be seen from the above that the presentinvention is advantageous in that it provides a flowmeter structure thatmaintains the dynamic isolation of the vibratory system of theflowmeter. It further permits the flowmeter to be tested, calibrated,and stored in a state in which it is devoid of a flange; the flangebeing installed only when the specific model of flange required by thecustomer is known.

[0017] An aspect of the invention includes:

[0018] A Coriolis flowmeter having a flow tube and a balance bar thatare adapted, when in use, to be vibrated in a driven plane in phaseopposition to generate a Coriolis response in said vibrating flow tuberepresenting information pertaining to material flowing through saidvibrating flow tube,

[0019] a case enclosing said flow tube and said balance bar with saidbalance bar being substantially parallel to and surrounding said flowtube;

[0020] a first and a second end of said case;

[0021] an opening in each of said case ends for receiving end portionsof said flow tube that project beyond said case ends;

[0022] said opening in said case ends is coaxial with a longitudinalaxis of said flow tube;

[0023] brace bar means coupling ends of said balance bar to said flowtube;

[0024] case connect link means having a first end coupled to said bracebar as well as to said balance bar and having a second end coupled to aninner wall of said case;

[0025] said case connect link means is effective to inhibit the movementof said brace bar and said balance bar ends in a direction perpendicularto said longitudinal axis of said flow tube in said driven plane;

[0026] a cone connect means having an outer circumference coupled tosaid case end and having a circular opening coaxial with said flow tubefor sealably receiving said flow tube; and

[0027] said cone connect means being axially positioned between aterminus of said flow tube and said case connect link means.

[0028] Another aspect comprises:

[0029] a cylindrical neck of said case end extending axially outwardfrom said case end;

[0030] said neck has a center opening coaxial with said flow tube and acylindrical inner surface that surrounds a portion of said flow tubethat projects beyond said case end;

[0031] said cylindrical inner surface of said neck has a greaterdiameter than the diameter of said flow tube; and

[0032] a circular cavity in said neck defined by the space between saidflow tube and said cylindrical inner surface of said neck.

[0033] Another aspect includes an out of plane bend in a planar surfaceof said case connect links.

[0034] Another aspect is that said circular cone connect means has aflat surface having an out of plane bend to permit a change in theeffective diameter of said circular cone connect means in response tochanges in the diameter of the portion of said case end to which saidcone connect means is coupled.

[0035] Another aspect is that said coupling of second end of said caseconnect link means comprises a connection of said second end of caseconnect link means to said inner wall of said case.

[0036] Another aspect is that said second end of said case connect linkmeans is coupled to said wall of said case by an intermediate connectionmeans that is connected to said inner wall of said case.

[0037] Another aspect is that said intermediate connection meansincludes a surface of said cone connect means whose perimeter isconnected to a surface of said inner wall of said case.

[0038] Another aspect is that a driver that vibrates said flow tube andsaid balance bar in a drive plane in phase opposition to each other;

[0039] said vibrations in said drive plane and said material flow arejointly effective for inducing Coriolis deflections in said flow tube;

[0040] pick off means coupled to said flow tube that detect saidCoriolis deflections;

[0041] said pick off means generate signals representing informationpertaining to said material flow in response to said detection of saidCoriolis deflections; and

[0042] meter electronics that receive said signals from said pick offmeans and generates output information pertaining to said material flow.

[0043] Another aspect is that said flow tube extends at a constantdiameter for the length of said case and has said ends portions thatproject through said opening in said cone connect means at said constantdiameter to said terminus of said flow tube.

[0044] Another aspect is that said terminus of each said end portion ofsaid flow tube is devoid of attachment to any other structure.

[0045] Another aspect includes an end flange coupled to said terminus ofeach said end portion of said flow tube for enabling said Coriolisflowmeter to be coupled to a pipeline;

[0046] a raised element having a circular opening on an axial end ofsaid flange, and

[0047] walls of said center opening that sealably engage said flow tube.

[0048] Another aspect includes a sealed cavity defined by space betweenthe outer surface of said end portion of said flow tube and said innercylindrical surface of said neck of said case end and a cylindricalinner surface of a portion of said end flange;

[0049] said sealed cavity having an axially outer end comprising openingof said raised element of said end flange sealably engaged with saidflow tube;

[0050] said sealed cavity having an axially inner end comprising saidopening in said cone connect means that is in sealable engagement withsaid flow tube.

[0051] Another aspect includes a sealed cavity defined by space betweenthe outer surface of a portion of said flow tube and an innercylindrical surface of said neck of said case end and a cylindricalinner surface of a neck of said end flange;

[0052] said sealed cavity has an axially outer end comprising saidraised element of said end flange that is sealably engaged with saidflow tube;

[0053] said sealed cavity has an axially inner end comprising saidopening in said cone connect means that is sealably engaged with saidflow tube.

[0054] Another aspect includes an end flange;

[0055] a neck of said end flange having a first end comprising said endflange and having second end connected to an axially outer end of saidneck of said case end;

[0056] a cylindrical opening in said end flange and in said neck of saidend flange for receiving said terminus of said end portion of said flowtube;

[0057] said cylindrical opening in said neck of said end flange and in aportion of said end flange has a diameter that is substantially greaterthan the exterior surface of said flow tube to define a void betweensaid exterior surface of said flow tube and said cylindrical innersurface of said neck of said end flange and a cylindrical inner surfaceof said portion of said end flange; and

[0058] a raised element having a center opening in an axially outerportion in said end flange that has an inner diameter for sealablyreceiving the terminus portion of said flow tube.

[0059] Another aspect includes said case includes walls parallel to thelongitudinal axis of said flow tube;

[0060] said case further includes said case ends which are affixed toends of said walls and are oriented substantially perpendicular to saidcylindrical walls;

[0061] the exterior surfaces of said case ends include a circular lipcoaxial with said opening in said case ends for defining said coneconnect means and for receiving said portion of said flow tube thatprojects beyond said case ends;

[0062] said case ends further including a neck having a cylindricalinner surface of a greater diameter than the exterior surface of saidflow tube to define a void comprising the space between said exteriorsurface of said flow tube and said inner surface of said neck.

[0063] Another aspect includes an end flange coupled to said terminus ofsaid flow tube for enabling said Coriolis flowmeter to be coupled to apipeline.

[0064] Another aspect includes cylindrical walls oriented parallel tothe longitudinal axis of said flow tube;

[0065] said case ends are curved and offset from perpendicular withrespect to said cylindrical walls;

[0066] an inner surface of a curved portion of said case end includesmeans that receives the outer extremity of said circular cone connectmeans;

[0067] said flow tube extends the length of said case and has said endportions that extend through a center opening of said cone connect meansand through said cavity of said neck of said case end to a flow tubeterminus axially beyond said neck.

[0068] Another aspect is that said terminus of said flow tube is devoidof attachment to any other structure.

[0069] Another aspect is that an end flange coupled to said terminus ofsaid flow tube for enabling said Coriolis flowmeter to be coupled to apipeline.

[0070] Another aspect includes cylindrical walls oriented parallel tothe longitudinal axis of said flow tube;

[0071] said case ends have a curved portion that is offset fromperpendicular with respect to said cylindrical walls;

[0072] an inner surface of an axial inner portion of said case end has adiameter equal to the inner diameter of said case for receiving theouter extremity of said circular cone connect means;

[0073] said flow tube extends the length of said case and has said endportions that extend through a center opening of said cone connect meansand through said cavity of said neck of said case end to a flow tubeterminus axially beyond said neck.

[0074] Another aspect is that said terminus of each said end portion ofsaid flow tube is devoid of attachment to any other structure.

[0075] Another aspect includes an end flange coupled to said terminus ofsaid flow tube for enabling said Coriolis flowmeter to be coupled to apipeline.

[0076] Another aspect is that said Coriolis flowmeter further includes:

[0077] an end flange;

[0078] a cylindrical opening in said end flange for receiving saidterminus of said end portion of said flow tube;

[0079] a neck of said end flange having a first end integral with anaxially outer portion of said end flange and having an axially inner endconnected to an axially outer end of said neck of said case end;

[0080] said end flange and said neck of said end flange both have acylindrical inner surface coaxial with said flow tube;

[0081] said cylindrical inner surface opening in said neck of said endflange as well as in an axially inner portion of said end flange has adiameter that is substantially greater than the exterior surface of saidflow tube to define a void between said exterior surface of said endportion of said flow tube and said cylindrical inner surface of saidneck of said end flange and said axially inner portion of said endflange; and

[0082] an axially outer portion of said cylindrical opening in said endflange defines a raised element that has a diameter approximate that ofsaid flow tube diameter for sealably receiving the terminus of said flowtube.

[0083] Another aspect is that said case connect link comprises:

[0084] a flat elongated member having a bend in a mid portion of saidmember to define two legs of said member that are angularly orientedwith respect to each other;

[0085] an outer end of a first one of said legs being connected to anend of said balance bar;

[0086] an outer end of a second one of said legs being connected to asurface of said cone connect means to define a series path connectingsaid end of said balance bar with said inner wall of said case;

[0087] said series path comprises said first and second legs of saidcase connect link and a portion of said cone connect means.

[0088] Another aspect includes said two legs are oriented substantially90 degree with respect to each other;

[0089] Another aspect is that said terminus of said flow tube is devoidof attachment to any other structure.

[0090] Another aspect includes an end flange coupled to said terminus ofsaid flow tube for enabling said Coriolis flowmeter to be coupled to apipeline.

[0091] Another aspect is that said case connect link comprises:

[0092] a flat elongated curvilinear member;

[0093] an outer end of a first one of said legs being connected to anend of said balance bar;

[0094] an outer end of a second one of said legs being connected to asurface of said cone connect means to define a series path connectingsaid end of said balance bar with said inner wall of said case;

[0095] said series path comprises said case connect link and a portionof said cone connect means.

[0096] Another aspect is that said case connect link comprises:

[0097] an elongated member having at least one bend;

[0098] an inner end of said elongated member is connected to an end ofsaid balance bar;

[0099] an outer end of said elongated member is connected to a surfaceof said cone connect means to define a series path connecting said endof said balance bar with said inner wall of said case;

[0100] said series path comprises said case connect link and a portionof said cone connect means.

[0101] Another aspect includes a method of forming a Coriolis flowmeterhaving a flow tube and a balance bar that are adapted, when in use, tobe vibrated in a driven plane in phase opposition to generate a Coriolisresponse in said vibrating flow tube representing information pertainingto material flowing through said vibrating flow tube, said methodcomprising the steps of:

[0102] enclosing said flow tube and said balance bar in a case with saidbalance bar being substantially parallel to said flow tube;

[0103] said case having first and a second ends;

[0104] including an opening defining a cone connect in each of said caseends for receiving end portions of said flow tube that project beyondsaid case ends;

[0105] sealably coupling said opening in said cone connect to said flowtube;

[0106] coupling ends of said balance bar to said flow tube with bracebar means;

[0107] coupling said brace bar and said balance bar to an inner wall ofsaid case with case connect link means;

[0108] said case connect link means is effective to inhibit the movementof said brace bar and said balance bar ends in a direction perpendicularto a longitudinal axis of said flow tube in said driven plane;

[0109] forming a cylindrical neck on said case end having a centercoaxial with said flow tube and extending axially outward from said caseend;

[0110] said neck surrounds said end portion of said flow tube thatprojects beyond said case end and has an inner cylindrical surface of agreater diameter than the diameter of said flow tube;

[0111] forming a circular cavity in said neck is defined by the spacebetween the outer surface of said end portion of said flow tube and saidcylindrical inner surface of said neck;

[0112] extending said flow tube at a constant diameter for the length ofsaid case so that said ends portions of said flow tube project throughsaid opening in each case end at said constant diameter to a terminusbeyond each said case end; and

[0113] said terminus of each end portion of said flow tube is devoid ofattachment to any other structure.

[0114] Another aspect includes the step of:

[0115] affixing an end flange to said terminus of said flow tube toenable said Coriolis flowmeter to be coupled to a pipeline.

DESCRIPTION OF THE DRAWINGS

[0116] The above and other objects and advantages of the invention maybe better understood from a reading of the following detaileddescription thereof taken in conjunction with the drawings in which:

[0117]FIGS. 1, 2, 3, 4, and 5 illustrate prior art Coriolis flowmeters;

[0118]FIG. 6 illustrates a first preferred exemplary embodiment of thepresent invention;

[0119]FIG. 7 illustrates another alternative exemplary preferredembodiment of the present invention and;

[0120]FIGS. 8 and 9 illustrate yet another preferred exemplaryembodiment of the present invention.

[0121]FIGS. 10 and 11 illustrate another preferred exemplary embodimentof the invention.

DETAILED DESCRIPTION

[0122] Description of FIG. 1

[0123]FIG. 1 discloses Coriolis flowmeter 100 of the U.S. Pat. No.5,473,949 to Cage. It is of the straight tube type and has a case 103enclosing a balance bar 102. The balance bar is cylindrical and enclosesflow tube 101. Case 103 has end elements 104 coupled by neck elements105 to input and output flanges 106. Element 107 is the input to theflowmeter; element 108 is the output. Flow tube 101 has an input end 109connected to an opening in case end 104 at element 112 which is thebrace bar portion of case end 104. Brace bar portion 112 is coupled toneck element 105. On the right side, the output end 110 of flow tube 101is coupled to the case end 104 at location 112 where case end 104 joinsneck element 105.

[0124] In operation flow tube 101 and balance bar 102 are vibrated inphase opposition by a driver (not shown). With material flow, thevibration of flow tube 101 induces a Coriolis response in flow tube 101that is detected by velocity sensors (not shown). The phase displacementbetween the velocity sensors represents information pertaining to theflowing material. The signal output of the velocity sensors is appliedto electronics circuitry that processes the signals to derive thedesired information pertaining to the material flow.

[0125] It is necessary that a Coriolis flowmeter provide accuratematerial flow information over a wide range of operating conditionsincluding materials of different density, temperature and viscosity. Inorder to achieve this, it is necessary that the vibration of thevibrating structure of the flowmeter be stable over this range ofconditions. In order to achieve this stability it is necessary that theflowmeter vibrations be isolated to the flow tube and balance barelements. The reason for this is that vibration external to thevibratory system imposes additional accelerations on the materialbesides the Coriolis acceleration that is used to determine the flowrate of the material. External vibration also moves the nodes definingthe active length of flow tube. The resulting acceleration is variableand subject to unknowable parameters such as mounting stiffness. Theundesired additional vibration of the vibratory structure of theflowmeter therefore impedes the ability of the flowmeter to provideaccurate output information regarding the material flow.

[0126] For the flowmeter of FIG. 1, the vibrating system includesbalance bar 102 and flow tube 101, which are vibrated in phaseopposition. These two elements comprise a dynamically balanced structurein which the ends 111 of balance bar and ends 109 and 110 of the flowtube are coupled by brace bar portion 112 of case end 104. This isundesirable since the processing of materials of different densities maycause the vibration amplitude of the balance bar 102 and the flow tube101 to vary.

[0127] Description of FIG. 2

[0128]FIG. 2 discloses the Coriolis flowmeter of U.S. Pat. No. 5,365,794to Krohne (FIG. 2 of U.S. Pat. No. 5,365,794). This patent disclosesCoriolis flowmeter 200 having a case 203 containing a flow tube 201 anda surrounding balance bar 202. Case 203 has a case end 204 that iscoupled by a neck element 205 to end flange 206. Flow tube 201 extendsthrough the entirety of the case and is coupled at its end 209 toportion 213 of end flange 206. Immediately to the right of flangeportion 213, is a void 214, which separates the inner wall of neckelement 205 from the outer surface of flow tube 201.

[0129] The flowmeter of FIG. 2 differs from that of FIG. 1 in that itincludes distinct brace bar 212 which couples the ends 211 of balancebar 202 to the outer surface of flow tube 201. In the flowmeter of FIG.2, the dynamically balanced vibrating system is balance bar 202, bracebar 212 and the flow tube 201. A node (point of no vibration) normallyresides in each brace bar 212. Under these conditions the meter isprocessing a material flow of a density for which the meter was designedand calibrated. The vibration amplitude of the balance bar 202 times itsmass is then equal to the vibration amplitude of the material filledflow tube 201 times its mass. When the flowmeter encounters materials ofa higher density, the vibration amplitude of the flow tube decreases andthe vibration amplitude of the balance bar increases. Similarly, whenmaterials of a lower density are encountered, the vibration amplitude ofthe flow tube increases and the vibration amplitude of the balance bardecreases. As the vibration amplitude ratio changes, the longitudinalaxis of flow tube sections 201L exits brace bar 212 at an angle to theflow meter. Under these conditions the balance bar applies a greaterbending torque to the brace bar region than the flow tube. The bendingcauses the case to translate downward (in phase with the heavy flowtube) while the brace bar regions translate upward (in phase with thebalance bar). These translations, as explained above can impair theaccuracy of the flow meter. The unbalanced torque can also stress themeter elements and in extreme cases, it can result in a shortened lifeor destruction of the flowmeter.

[0130] Description of FIGS. 3, 4, and 5

[0131]FIGS. 3, 4, and 5 show a left portion of the flowmeter of EPOPatent EP 0 759 542 A1 (FIG. 8b of EPO Patent EP 0 759 542 A1). Theflowmeter of FIG. 3 is similar to that of FIG. 2 in that it has a case403, a case end 404, a case neck 405 and end flanges 406. Case 403encloses flow tube 401 which is surrounded by balance bar 402. Bracebars 412 couple balance bar end 411 to flow tube 401. The flow tube end407 is connected by flow tube end portion 410 to portion flange element413 which is a part of flange 406. The flowmeter of FIG. 3 is similar tothat of FIG. 2 in that it has a void 414 between the exterior surface offlow tube portion 401L and the inner wall of neck 405 connecting caseend 404 to end flange 406.

[0132] The flowmeter of FIG. 3 differs from that of FIG. 2 in that flowtube end element 410 is larger in diameter than flow tube 401. Thechange in diameter between flow tube element 410 and flow tube 401serves the purpose of relieving thermal stresses in the flow tube.Another distinction between the flowmeter of FIG. 3 and that of FIG. 2is that the flowmeter of FIG. 3 has case connect link elements 417 eachof which has a first end 418 coupled to an inner wall 420 of case 403and a second end coupled to the end 411 of balance bar 402.

[0133] Case connect links 417 overcome some of the vibration problemsdescribed for the flowmeter of FIG. 2. The flowmeter structure of FIG. 2permits the ends of the balance bar 202 and brace bar 212 to vibratewith respect to the inner wall of case 203. This is prevented in theflowmeter of FIG. 3 since case connect links 417 provide a rigidconnection between the balance bar ends 411 and the inner wall 420 ofcase 403. In such structures, the location where the case connect links417 join to the balance bar end acts as a pivot point 508 for thevibrations of flow tube 401 and balance bar 402. Thus the balance barend cannot translate with respect to the inner wall of case 403 byvirtue of the connection between the two elements provided by caseconnect links 417. However, as shown in FIG. 4, balance bar 402, flowtube 401 and brace bar 417 can become a dynamically unbalanced structurewhen materials having a significantly higher or significantly lowerdensity than normal are processed. The change in amplitude ratio of theelements to the right of pivot point 508 can apply an undesirable torqueto portion 401L of the flow tube 401 resulting forces F1 and F2.

[0134]FIG. 5 is an end view of the flowmeter structure of FIG. 4 takenalong line 5-5 of FIG. 4. FIG. 5 shows flow tube 401 brace bar 412, caseconnect links 417 having outer ends 418 connected to the inner wall 420of case 403 and an inner end 419 connected to the outer extremity ofbrace bar 412. Case connect links 417 are flat strips. FIG. 3 is a topview of a section of flowmeter 400; FIG. 4 is a side section view.

[0135] Description of FIG. 6

[0136]FIG. 6 discloses one possible exemplary embodiment of theinvention as comprising a flowmeter 700 having a case 703 that enclosesthe elements that comprise the vibrating system of the flowmeter. Theseelements include a balance bar 702 which surrounds a center portion offlow tube 701. Balance bar 702 is connected at its ends by a brace bars709 to flow tube 701. The flow tube 701 includes extensions 701L at theinput end and 701R at the output end of the flowmeter. These flow tubeelements together comprise a single flow tube that extends at a constantdiameter through the flowmeter 700. In so doing, flow tube 701 extendsfor the length of case 703, through case ends 704 and projects beyondcase ends 704 to terminus 707 on the left and terminus 708 on the right.Element 707 may be considered to be the input end of the flow tube;element 708 may be considered to be the output end of the flow tube. Thecase ends 704 have a center portion 723 termed a cone connect having anopening through which tube portion 701L extends on the left and throughwhich flow tube portion 701R extends on the right. Cone connect 723sealably engages the exterior surface of flow tube elements 701L and701R. Case end 704 has a thickness essentially the same as that of case703. The radially center portion of the case ends 704 includes a lip722. Lip 722 extends axially outward beyond the outer surface of caseend 704 and its cone connect 723. The inner surface of lip 722 has adiameter that is essentially the same as the outer diameter of coneconnect 723. The inner diameter of the lip of 722 and the outer diameterof the flow tube forms a void 721.

[0137] The ends of balance bar 702 are coupled by brace bars 709 to theouter surface of flow tube 701. Brace bars 709 form a path that permitsbalance bar 702, brace bars 709, and flow tube 701 to be a dynamicallybalanced system with the balance bars 702 and the flow tube 701dynamically communicating with each other via brace bars 709. The endsof balance bars 702 are further coupled by means of case connect links710 to the inner wall 712 of case 703. Case connect links 710 include afold element 711. Case connect links 710 are coupled at their outer end706 to the inner case wall 712 and at their inner end 705 to balance bar702.

[0138] The case connect links 710 of FIG. 6 are similar to case connectlinks 417 on FIG. 3 in that they couple the ends 705 of balance bar 702on FIG. 6 to the inner wall 712 of case 703. Their function is toprevent vibrations of brace bar 709 in a direction perpendicular to thetube axis in the drive plane of FIG. 6. The case connect links 710 serveto keep the unbalanced torques from moving the brace bar 709 withrespect to the case. This enables the vibration amplitude ratio tochange with density so as to keep the vibrating structure balanced.However, as distinguished from case connect links 417, case connectlinks 710 have an out of plane bend. Balance bar 702 and the case 703can change in diameter with respect to each other in response totemperature differentials between these two elements. Bend 711 permitsthe effective length of case connect link 710 to change as the casediameter and the balance bar diameter attempt to expand or contract withrespect to each other.

[0139] Driver D and a left velocity sensor LPO and a right velocitysensor RPO are shown coupled to flow tube 701 on FIG. 6. These elementsare connected in a manner similar to that shown in greater detail onFIG. 7 to meter electronics element 801. Meter electronics 801 suppliesa signal via path 803 to driver D to vibrate flow tube 701 totransversely at the resonant frequency of flow tube 701 with materialflowing therein. The combined material flow and vibrations imparted toflow tube 701 by driver D induces a Coriolis response in flow tube 701in a manner well known in the art. The phase difference between thesignals of left velocity sensor LPO and right velocity sensor RPOrepresents information pertaining to the material flow. The outputsignals of the velocity sensors are applied as shown on FIG. 7 via paths802 and 804 to meter electronics 801 which processes the receivedsignals and generates output information on its path 815 pertaining thematerial flow.

[0140] It should be noted that the flow tube ends 707 and 708 are notconnected to flange elements as is the case for flowmeter of FIG. 7. Theflowmeter of FIG. 6 is manufactured, tested, and calibrated withoutflanges being attached to the flow tube ends. The prior art meters ofFIGS. 2 through 5 could not be balanced and tested prior to the flangesbeing attached because the tube end connections were critical to thedynamics of the vibrating structure. The cone connect elements 723 ofthe present invention remove the tube ends 707 and 708 from the dynamicstructure of the meter and create a fully functional meter prior to theflange welding operation.

[0141] Suitable facilities are provided at the location at which theflowmeter of FIG. 6 is calibrated and tested to permit the flow tubeends 707 and 708 to be coupled to a source of material flow at anappropriate pressure to permit the calibration and testing to beaccomplished. Once this testing and calibration is accomplished, theflowmeter of FIG. 6 may be stored until it is ready for delivery to acustomer. The manufacture testing, calibration and temporary storage ofthe flowmeter of FIG. 6 without flanges is advantageous since there aremany different types of flanges. It is economically advantageous tomanufacture, calibrate, test, and store a flowmeter in its condition asshown in FIG. 6 until such time as a customer for the flowmeter is knownand the type of flange desired by the customer is also known. At thattime, the flanges desired by the customer are attached and the

[0142] Flow meter is equipped as shown in FIG. 7. It is advantageous tocalibrate, test and store the flowmeter equipped as shown in FIG. 6since it minimizes the inventory that a manufacture must maintain.

[0143] Description of FIG. 7

[0144] The flowmeter of FIG. 7 is identical to that of FIG. 6 exceptthat the flowmeter of FIG. 7 includes flanges 806 affixed to the endportions 701L and 701R of flow tube 701. Flanges 806 include an outerend surface 807, an inner surface 809 parallel to outer surface 807, aneck 805 having an inner axial end surface which contacts a mating outeraxial end surface of lip 722 of case end 704. Outer surface 807 offlange element 806 has a raised element 827 having a center openingwhose walls sealably contact flow tube 701L at its inlet 707 and 701R atoutlet 708. A void 721 is defined by the space between the exteriorsurface of flow tube 701 intermediate raised element 827 of flange 806and lip 722 coupled to case end 704. Void 721 is advantageous in that itpermits flange 806 to be coupled to case end 704 at lip 722. Since thiscoupling involves a heating operation, such as brazing or welding, flowtube 701 L and 701 R is subject to less thermal stress by virtue of thevoid 721. If the void 721 comprised solid material, the heat from thewelding of the flange 806 to lip 722 could be conducted to and overheatthe portions of flow tube flow tube 701L and 701R. This large amount ofheat could alter the structure of the flow tube material, such astitanium, in such a way as to decrease its corrosion resistance. Theheat of the weld could also partially melt the braze material in thejoint between flow tube 701 and cone connect 723. This could harm thebraze and could possibly affect the prior calibration and adjustment offlowmeter in its state of completion as shown on FIG. 6.

[0145] The flowmeter of FIG. 7 provides three connection points betweenflow tube 701 and case 703 near each end of flow tube 701. The firstconnecting point is that provided by the end flanges 806 which have thecenter opening of raised element 827 whose walls are bonded to flow tubeends 701L and 701R. The second connecting point is cone connect 723 ofcase end 704. The third connecting point is provided by brace bars 709together with case connect links 710. These three connecting pointsaffix flow tube 701 to the structural elements of flowmeter case 703.

[0146] The function of the connecting point comprising the caseconnection links 710 and the brace bar 709 is to minimize translationsto the flow tube end nodes where they are coupled to brace bar 709. Thefunction of the junction point provided by raised element 827 and thewalls of its center opening is to seal the flow tube 701 to the flange806 so as to prevent the material flow from entering case 703. Thefunction provided by cone connect 723 is to provide a rigid terminationfor the dynamic portion of the flow tube. This connection applies to thecase end the force generated by unbalanced torque at the brace barregion. The case and case end are rigid enough to withstand this forcewithout significant bending. Moving the torque reaction force (FIG. 4)to the case end eliminates communication to the vibratory structure ofthe flowmeter. The intermediate connection also reduces stress on thejunction between the flow tube ends 707 and 708 and raised element 827and thereby increases reliability.

[0147] Description of FIGS. 8 and 9

[0148]FIGS. 8 and 9 disclose another possible exemplary embodiment ofthe invention. The embodiment of FIG. 8 is similar to that of FIGS. 6and 7 in that the flowmeter 900 of FIG. 8 has case 903 that encloses abalance bar 902 and a flow tube 901. FIG. 8 discloses only a leftportion of flowmeter 900 to minimize drawing complexity. Also, thedriver D and the two velocity sensors LPO and RPO are not shown on FIG.8 nor is the associated meter electronics. It is to be understood thatthe flowmeter of FIG. 8 includes a driver element D, a left velocitysensor LPO and a right velocity sensor RPO all of which are connectedover appropriate conductors to a meter electronics element which appliesa drive signal for the driver to vibrate the balance bar and flow tubeand which receives the signals from the two velocity sensors, andprocesses them to generate material flow information for the materialflowing through flow tube 901 as it is vibrated by the driver D (notshown).

[0149] In a manner similar to that shown on FIGS. 6 and 7, the left endof balance bar 902 is connected at junction 905 to the lower end of acase connect link 910 having a fold 911 with the outer end 920 of thecase connect link 910 being connected to an inner wall 912 of case 903.Case connect link 910 performs the same function as that for caseconnect link 710 on FIG. 6. They similarly stabilize the vibrations ofbalance bar 902 and flow tube with respect to vibrations in the driveplane (perpendicular to the plane of the paper on which FIG. 8 isillustrated).

[0150] Flow tube 901 extends for the length of balance bar 902 andfurther extends axially through a disc like cone connect member 923which is shown in detail on FIG. 9. Flow tube 901 extends through anopening 926 in cone connect member 923 and further extends as element901L to its input end 907 where it is connected by raised element 927 toflange 906. Flange 906 has an outer axial surface 904, an outercircumferential surface 908 and an inner axial surface 909.

[0151] Flange 906 has a neck 925 that is coupled by means of a weld 922to a neck 924 of the end of case 903. Neck 924 is similar to lip 722 ofthe flowmeter of FIG. 6. The difference is that while the lip 722 ofcase end 704 is relatively small compared to case end 704, neck 924 ofcase end 928 projects axially towards surface 909 of end flange 906 agreater distance than does lip 721 of FIG. 6.

[0152] Void 930 defines the space between the exterior surface of flowtube 901L and the inner radial surfaces of neck 925 and neck 924. Void930 serves the same function as does void 721 on FIG. 7; namely, itminimizes the heat that is conducted from the weld 922 to the flow tube901L. This protects the flow tube 901L and the braze joint of opening926 from the heat of the flange weld 922.

[0153] Cone connect member 923 is shown in further detail on FIG. 9 ascomprising a circular element having an outer circumference 932 which iscoupled to a notch in the inner surface 929 of case end 928. Coneconnect member 923 has a flat surface 1002 adjacent its circumference932. Near the radial mid point the surface 1002 becomes groove 1003which, in turn, becomes a flat surface 1005 comprising the inner radialportion of cone connect 923. The center of flat surface 1005 has anopening 926 through which flow tube 901 extends with the flow tube andsurface 1005 being coupled to one another. Groove 1003 enhances theability of the cone connect 923 to accommodate differential expansiondue to temperature differences between the flow tube 901 and the case903. It also protects the completed flowmeter from excessive thermalaxial stresses.

[0154] The structure comprising case 903 and end flanges 906 offlowmeter 900 are coupled to the flow tube at three points per end inthe same manner as the flow tube of FIG. 7. The first point of couplingis that between raised element 927 and flow tube end 907. A second pointof coupling is that between flow tube 901 and cone connect member 923.The third point of coupling is that provided by case connect link 910between the inside surface of the case 903 and the end of balance bar902. The end of balance bar 902 is in turn connected to flow tube 901 bythe brace bar (not shown).

[0155] Description of FIGS. 10 and 11

[0156]FIGS. 10 and 11 disclose an alternative embodiment of theinvention that is similar in many respects to that shown on FIGS. 8 and9. The two embodiments are similar in most respects and differ only withrespect to the details of the elements 923 and 910 on FIG. 8 which arethe cone connect element and case connect links respectively.Corresponding elements on FIGS. 10 and 11 are designated 1123 and 1110with 1123 being the cone connect element and with element 1110 being thecase connect link.

[0157] The elements on FIGS. 10 and 11 that have reference numbers inthe 900 series (i.e. 902, 903, . . . etc.) are identical to thecorresponding numbered elements of FIG. 8 which have already beendescribed in detail in connection with FIG. 8. The elements of FIG. 10that differ from those on FIG. 8 are designated with reference numbersin the 1100 series (i.e. 1102, 1103, . . . etc.).

[0158] Cone connect element 1123 of FIG. 10 differs from its counterpart923 on FIG. 8 in that cone connect 1123 has a larger diameter thatextends from one inner surface 912 of case end 928 to the inner wall onthe opposite side of the case end. Because of this, cone connect 1123 ispositioned somewhat to the right on FIG. 10 and adjacent the weldportions 921 of the case 903. The cone connect 923, by way ofcomparison, is positioned more to the left on FIG. 8 and has itscircumference recessed within notches of the inner case end wall. Coneconnect 1123 is shown in greater detail on FIG. 11 and has its outercircumference 1129 contacting inner wall 912 on FIG. 10. Immediatelyadjacent the outer circumference 1129 is a flat portion 1102 as shownboth on FIGS. 10 and 11. The inner portion of flat surface 1102 engagesa curved surface 1103 as shown on FIGS. 10 and 11 with the curvedsurface 1103 having a bowl like configuration. The inner extremity ofbowl like surface 1103 becomes the outer extremity of a flat surface1104 as shown on both FIGS. 10 and 11. Flat surface 1104 has a centeropening 1126 through which flow tube 901 projects. The bowl like surface1103 performs the dual function of accommodating an axially movement offlow tube 901 due to thermal expansion/contraction as well asaccommodating changes in the inner diameter of case 903 due to thermalchanges.

[0159] Case connect link 1110 is not identical to case connect link 910on FIG. 8. On FIG. 8, case connect link 910 is directly connected at itsends between the inner surface 912 of case 903 and the junction of theleft end 905 of balance bar 902 and the brace bar. The case connect link1110 is different in that its has a bend in its middle and therebycomprises legs 1107 and 1108 with the leg 1108 being connected atjunction 1105 to the left end of balance bar 902 and the brace bar.Alternatively, case connect link 1110 may be of a continuously curvedconfiguration. The other portion 1107 of the case connect link isconnected at its end 1106 to flat surface 1102 of cone connect 1123. Thebend or curve in case connect link 1110 permits it to flex andaccommodate changes in the diameter of balance bar 902 due to thermalchanges. Case connect link 1110 is thus connected between the balancebar at junction 1105 and the inner wall 912 of case 903 by means of aseries connection of the case connect link and a portion of the flatsurface 1102 of cone connect 1123. This series connection has sufficientstrength to inhibit undesired vibrational translations between thejunction of the brace bar, flow tube, and balance bar with respect tothe inner wall 912 of case 903.

[0160] It is to be expressly understood that the claimed invention isnot to be limited to the description of the preferred embodiment butencompasses other modifications and alterations within the scope andspirit of the inventive concept. For example, although the presentinvention has been disclosed as comprising a part of a single straighttube Coriolis flowmeter, it is to be understood that the presentinvention is not so limited and may be used with other types of Coriolisflowmeters including single tube flowmeters of irregular or curvedconfiguration as well as Coriolis flowmeters having a plurality of flowtubes. Also, raised elements 827 and 927 may either be integral withtheir respective flanges 806 and 906 or they may be separate elementsaffixed to their respective flanges. In Coriolis flowmeters made of asingle material, such as stainless steel, raised elements 827 and 927may be integral with and formed or the same stainless steel as theirrespective flanges. It is sometimes desired that Coriolis flowmeters usedifferent materials for their different parts. In such flowmeters, theflow tube may be titanium and the case and flanges may be stainlesssteel. Also the raised inserts 827 and 927 may also be titanium toprovide a flow path that is all titanium. In such flowmeters thetitanium inserts 827 and 927 would be separate elements from thestainless steel flanges and would be affixed to the flanges byappropriate bonding techniques.

What is claimed is:
 1. In a Coriolis flowmeter having a flow tube and abalance bar that are adapted, when in use, to be vibrated in a drivenplane in phase opposition to generate a Coriolis response in saidvibrating flow tube representing information pertaining to materialflowing through said vibrating flow tube, said Coriolis flowmetercomprising: a case enclosing said flow tube and said balance bar withsaid balance bar being substantially parallel to and surrounding saidflow tube; a first and a second end of said case; an opening in each ofsaid case ends for receiving end portions of said flow tube that projectbeyond said case ends; said opening in said case ends is coaxial with alongitudinal axis of said flow tube; brace bar means coupling ends ofsaid balance bar to said flow tube; case connect link means having afirst end coupled to said brace bar means as well as to said balance barand having a second end coupled to an inner wall of said case; said caseconnect link means is effective to inhibit the movement of said bracebar and said balance bar ends in a direction perpendicular to saidlongitudinal axis of said flow tube in said driven plane; a cone connectmeans having an outer circumference coupled to said case end and havinga circular opening coaxial with said flow tube for sealably receivingsaid flow tube; and said cone connect means being axially positionedbetween a terminus of said flow tube and said case connect link means.2. The Coriolis flowmeter of claim 1 further comprising: a cylindricalneck of said case end extending axially outward from said case end; saidneck has a center opening coaxial with said flow tube and a cylindricalinner surface that surrounds a portion of said flow tube that projectsbeyond said case end; said cylindrical inner surface of said neck has agreater diameter than the diameter of said flow tube; and a circularcavity in said neck defined by the space between said flow tube and saidcylindrical inner surface of said neck.
 3. The Coriolis flowmeter ofclaim 1 further including an out of plane bend in a planar surface ofsaid case connect links.
 4. The Coriolis flowmeter of claim 1 whereinsaid circular cone connect means has a flat surface having an out ofplane bend to permit a change in the effective diameter of said circularcone connect means in response to changes in the diameter of the portionof said case end to which said cone connect means is coupled.
 5. TheCoriolis flowmeter of claim 1 wherein said coupling of a second end ofsaid case connect link means comprises a connection of said second endof case connect link means to said inner wall of said case.
 6. TheCoriolis flowmeter of claim 1 wherein said second end of said caseconnect link means is coupled to said wall of said case by anintermediate connection means that is connected to said inner wall ofsaid case.
 7. The Coriolis flowmeter of claim 5 wherein saidintermediate connection means includes a surface of said cone connectmeans whose perimeter is connected to a surface of said inner wall ofsaid case.
 8. The Coriolis flowmeter of claim 1 further includes: adriver that vibrates said flow tube and said balance bar in a driveplane in phase opposition to each other; said vibrations in said driveplane and said material flow are jointly effective for inducing Coriolisdeflections in said flow tube; pick off means coupled to said flow tubethat detect said Coriolis deflections; said pick off means generatesignals representing information pertaining to said material flow inresponse to said detection of said Coriolis deflections; and meterelectronics that receive said signals from said pick off means andgenerates output information pertaining to said material flow.
 9. TheCoriolis flowmeter of claim 2 wherein said flow tube extends at aconstant diameter for the length of said case and has said ends portionsthat project through said opening in said cone connect means at saidconstant diameter to said terminus of said flow tube.
 10. The Coriolisflowmeter of claim 9 wherein said terminus of each said end portion ofsaid flow tube is devoid of attachment to any other structure.
 11. TheCoriolis flowmeter of claim 9 further including: an end flange coupledto said terminus of each said end portion of said flow tube for enablingsaid Coriolis flowmeter to be coupled to a pipeline; a raised elementhaving a circular opening on an axial end of said end flange, and a wallon an inner surface of said circular opening that engages said flowtube.
 12. The Coriolis flowmeter of claim 11 further including: a sealedcavity defined by space between the outer surface of said end portion ofsaid flow tube and said inner cylindrical surface of said neck of saidcase end and a cylindrical inner surface of a portion of said endflange; said sealed cavity having an axially outer end comprising saidraised element of said end flange sealably engaged with said flow tube;said sealed cavity having an axially inner end comprising said openingin said cone connect means that is in sealable engagement with said flowtube.
 13. The Coriolis flowmeter of claim 12 further including: a sealedcavity defined by space between the outer surface of a portion of saidflow tube and an inner cylindrical surface of said neck of said case endand a cylindrical inner surface of a neck of said end flange; saidsealed cavity has an axially outer end comprising said raised element ofsaid end flange that is sealably engaged with said flow tube; saidsealed cavity has an axially inner end comprising said opening in saidcone connect means that is sealably engaged with said flow tube.
 14. TheCoriolis flowmeter of claim 9 further including: an end flange; a neckof said end flange having a first end comprising said end flange andhaving second end connected to an axially outer end of said neck of saidcase end; a cylindrical opening in said end flange and in said neck ofsaid end flange for receiving said terminus of said end portion of saidflow tube; said cylindrical opening in said neck of said end flange andin a portion of said end flange has a diameter that is substantiallygreater than the exterior surface of said flow tube to define a voidbetween said exterior surface of said flow tube and said cylindricalinner surface of said neck of said end flange and a cylindrical innersurface of said portion of said end flange; and a raised element in anaxially outer portion of said end flange having a cylindrical openingwhose walls have an inner diameter that sealably receive the terminusportion of said flow tube.
 15. The Coriolis flowmeter of claim 2wherein: said case includes walls parallel to the longitudinal axis ofsaid flow tube; said case further includes said case ends which areaffixed to ends of said walls and are oriented substantiallyperpendicular to said cylindrical walls; the exterior surfaces of saidcase ends include a circular lip coaxial with said opening in said caseends for defining said cone connect means and for receiving said portionof said flow tube that projects beyond said case ends; said case endsfurther including a neck having a cylindrical inner surface of a greaterdiameter than the exterior surface of said flow tube to define a voidcomprising the space between said exterior surface of said flow tube andsaid inner surface of said neck.
 16. The Coriolis flowmeter of claim 15further including: an end flange coupled to said terminus of said flowtube for enabling said Coriolis flowmeter to be coupled to a pipeline.17. The Coriolis flowmeter of claim 9 wherein said case comprises:cylindrical walls oriented parallel to the longitudinal axis of saidflow tube; said case ends are curved and offset from perpendicular withrespect to said cylindrical walls; an inner surface of a curved portionof said case end includes means that receives the outer extremity ofsaid circular cone connect means; said flow tube extends the length ofsaid case and has said end portions that extend through a center openingof said cone connect means and through said cavity of said neck of saidcase end to a flow tube terminus axially beyond said neck.
 18. TheCoriolis flowmeter of claim 17 wherein said terminus of said flow tubeis devoid of attachment to any other structure.
 19. The Coriolisflowmeter of claim 17 further including: an end flange coupled to saidterminus of said flow tube for enabling said Coriolis flowmeter to becoupled to a pipeline.
 20. The Coriolis flowmeter of claim 9 whereinsaid case comprises: cylindrical walls oriented parallel to thelongitudinal axis of said flow tube; said case ends have a curvedportion that is offset from perpendicular with respect to saidcylindrical walls; an inner surface of an axial inner portion of saidcase end has a diameter equal to the inner diameter of said case forreceiving the outer extremity of said circular cone connect means; saidflow tube extends the length of said case and has said end portions thatextend through a center opening of said cone connect means and throughsaid cavity of said neck of said case end to a flow tube terminusaxially beyond said neck.
 21. The Coriolis flowmeter of claim 20 whereinsaid terminus of each said end portion of said flow tube is devoid ofattachment to any other structure.
 22. The Coriolis flowmeter of claim20 further including: an end flange coupled to said terminus of saidflow tube for enabling said Coriolis flowmeter to be coupled to apipeline.
 23. The Coriolis flowmeter of claim 20 wherein said Coriolisflowmeter further includes: an end flange; a cylindrical opening in saidend flange for receiving said terminus of said end portion of said flowtube; a neck of said end flange having a first end integral with anaxially outer portion of said end flange and having an axially inner endconnected to an axially outer end of said neck of said case end; saidend flange and said neck of said end flange both have a cylindricalinner surface coaxial with said flow tube; said cylindrical innersurface opening in said neck of said end flange as well as in an axiallyinner portion of said end flange has a diameter that is substantiallygreater than the exterior surface of said flow tube to define a voidbetween said exterior surface of said end portion of said flow tube andsaid cylindrical inner surface of said neck of said end flange and saidaxially inner portion of said end flange; and an axially outer portionof said end flange defines a raised element having a center openingwhose inner walls have a diameter approximate that of said flow tubediameter for sealably receiving the terminus of said flow tube.
 24. TheCoriolis flowmeter of claim 20 wherein said case connect link comprises:a flat elongated member having a bend in a mid portion of said member todefine two legs of said member that are angularly oriented with respectto each other; an outer end of a first one of said legs being connectedto an end of said balance bar; an outer end of a second one of said legsbeing connected to a surface of said cone connect means to define aseries path connecting said end of said balance bar with said inner wallof said case; said series path comprises said first and second legs ofsaid case connect link and a portion of said cone connect means.
 25. TheCoriolis flowmeter of claim 24 wherein said two legs are orientedsubstantially 90 degree with respect to each other;
 26. The Coriolisflowmeter of claim 24 wherein said terminus of said flow tube is devoidof attachment to any other structure.
 27. The Coriolis flowmeter ofclaim 24 further including: an end flange coupled to said terminus ofsaid flow tube for enabling said Coriolis flowmeter to be coupled to apipeline.
 28. The Coriolis flowmeter of claim 20 wherein said caseconnect link comprises: a flat elongated curvilinear member; an outerend of a first one of said legs being connected to an end of saidbalance bar; an outer end of a second one of said legs being connectedto a surface of said cone connect means to define a series pathconnecting said end of said balance bar with said inner wall of saidcase; said series path comprises said case connect link and a portion ofsaid cone connect means.
 29. The Coriolis flowmeter of claim 20 whereinsaid case connect link comprises: an elongated member having at leastone bend; an inner end of said elongated member is connected to an endof said balance bar; an outer end of said elongated member is connectedto a surface of said cone connect means to define a series pathconnecting said end of said balance bar with said inner wall of saidcase; said series path comprises said case connect link and a portion ofsaid cone connect means.
 30. A method of forming a Coriolis flowmeterhaving a flow tube and a balance bar that are adapted, when in use, tobe vibrated in a driven plane in phase opposition to generate a Coriolisresponse in said vibrating flow tube representing information pertainingto material flowing through said vibrating flow tube, said methodcomprising the steps of: enclosing said flow tube and said balance barin a case with said balance bar being substantially parallel to saidflow tube; said case having first and a second ends; including anopening defining a cone connect in each of said case ends for receivingend portions of said flow tube that project beyond said case ends;sealably coupling said opening in said cone connect to said flow tube;coupling ends of said balance bar to said flow tube with brace barmeans; coupling said brace bar and said balance bar to an inner wall ofsaid case with case connect link means; said case connect link means iseffective to inhibit the movement of said brace bar and said balance barends in a direction perpendicular to a longitudinal axis of said flowtube in said driven plane; forming a cylindrical neck on said case endhaving a center coaxial with said flow tube and extending axiallyoutward from said case end; said neck surrounds said end portion of saidflow tube that projects beyond said case end and has an innercylindrical surface of a greater diameter than the diameter of said flowtube; forming a circular cavity in said neck is defined by the spacebetween the outer surface of said end portion of said flow tube and saidcylindrical inner surface of said neck; extending said flow tube at aconstant diameter for the length of said case so that said ends portionsof said flow tube project through said opening in each case end at saidconstant diameter to a terminus beyond each said case end; and saidterminus of each end portion of said flow tube is devoid of attachmentto any other structure.
 31. The method of claim 30 in combination withthe step of: affixing an end flange to said terminus of said flow tubeto enable said Coriolis flowmeter to be coupled to a pipeline.
 32. TheCoriolis flowmeter of claim 1, formed by the steps of: enclosing saidflow tube and said balance bar in said care, sealably coupling saidopening in said cone connect to said flow tube; coupling ends of saidbalance bar to said flow tube with brace bar means; coupling said bracebar and said balance bar to an inner wall of said case with case connectlink means; forming a cylindrical neck on said case end having a centercoaxial with said flow tube and extending axially outward from said caseend; said neck surrounds said end portion of said flow tube thatprojects beyond said case end and has an inner cylindrical surface of agreater diameter than a diameter of said flow tube; forming a circularcavity in said neck is defined by the space between the outer surface ofsaid end portion of said flow tube and said cylindrical inner surface ofsaid neck; extending said flow tube at a constant diameter for thelength of said case so that said ends portions of said flow tube projectthrough said opening in each case end at said constant diameter to aterminus beyond each said case end; and said terminus of each endportion of said flow tube is devoid of attachment to any otherstructure.